Oscillating abutment rotary pump



Dec. 27, 1949 JOHNSON 2,492,869

OSCILLATING ABUTMENT ROTARY PUMP Filed April 8, I946 2 Shets-Sheet lINVENTOR. JAMES F! JOHNSON Dec. 27, 1949 Filed April 8,

J. P; JOHNS-QN 2,492,869

'OSCILLATING ABUTMEN'I ROTARY PUMP 2 Sheets-Shet 2 r km cos36 IINVENTOR. JAMES F! JOHNSON ATTORNEYS Patented Dec. 27, 1949 2,492,869OSCILLATING ABUTMENT ROTARY PUlVIP James P. Johnson, Shaker Heights,Ohio Application April 8, 1946, Serial No. 660,494

5 Claims.

The present invention relates to improvements rangement for eliminatingpulsation in the delivery of the pump and also mechanical shock therein.

It is another object of this invention to provide a pump which can beoperated at high speeds without throwing the vanes toward or away as thecase may be from the cam surface which actuates the same.

It is another object of this invention to provide a pump in which thevanes are positively actuated so as not to become inoperative when thepump is used for pressurizing highly viscous fluids.

It is another object of this invention to provide novel means formaintaining the vanes in continuous sealing engagement with the camsurface which actuates the same.

It is another object of this invention to provide novel means forassuring that the rotor will operate freel and efficiently in spite ofirregularities in the vane actuating cam surface thereof.

Additional objects and advantages of the invention will become apparentas the following description proceeds.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawings setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

In the drawings:

Fig. 1 is an end view of one form of my invention with the cover platethereof removed to clearly illustrate the construction of the vanes,rotor and stator;

Fig. 2 is a longitudinal cross section view taken alongline 2-2 of- Fig.1;

which is capable of displacing passages 9 and I0 and Fig. 3 is an endview similar to that of Fig. 1 except showing a modified form of vanetherein;

Fig. 4 is a longitudinal cross section view taken along the line 4-4 ofFig. 3;

Fig. 5 is a view similar to that of Fig. 1 except that it shows asimplified form of recess for vanes which are of considerable length;

Fig. 6 is a longitudinal cross section view taken along line 6-6 of Fig.5;

Fig. '7 is a fragmentary end view similar to that of Fig. 1 except thatit shows a vane which is capable of yielding to accommodate variation orirregularity in the cam surface of the rotor;

Fig. 8 is a perspective view of the vane shown in Figs. 1 and 5;

Fig. 9 is a diagrammatic preferred form of vane actuating cam surface;and

Fig. 10 is a diagrammatic developed view of a modified form of vaneactuating cam surface.

Referring now to the drawings and first'generally to Figs. 1-7 whereinlik parts are designated by like numerals, there is shown therein foursubstantially identical pumps each of which comprises a stator l havinga cylindrical bore 2 therein closed by a cover plate 3 which defineswith such bore a pump chamber. rotatably mounted within such pumpchamber in suitable bearings 5 and 6 in the stator and cover platerespectively and is in sealing contact with the end walls 1 and 8 ofsuch chamber.

and also with circumferentially spaced points about the cylindrical wallof bore 2.

The stator I is provided in the wall of its bore 2 with adjacent pairsof diametrically opposed passages 9, l0 and II, l2 and in the preferredarrangement wherein the rotor is intended to be rotated clockwise, asviewed in Figs. 1, 3, 5 and 7, passages 9 and I0 are joined into asingle discharge passage not shown and passages II and I2 are joinedinto a single inlet passage not shown. It is to be understood that therotor.

can with equal facility be rotated counter-clockwise, as viewed in thesefigures, in which case, H and I2 will be inlet and discharge passagesrespectively. It is also to be understood that while the term pump isused throughout the specification and claims, my invention can energy offluid under pressure into mechanical rotation.

Stator I is provided with diametrically opposed recesses !3 and [4 ofcylindrical form which intersect the cylindrical wall of bore 2 andwhich have axes parallel to that of bore 2, such recessesdeveloped viewof the- A rotor 4 is be used as a motor to translate,

being less than fully cylindrical and preferably approximatelysemi-cylindrical as shown. In the form of pump shown in Figs. 1 and 7,such recesses include both an inner wall and an outer wall foraccurately slide guiding the hereinafter to be described vanes which aredisposed in such recesses. In order to preclude the possibility ofdisplacement of the sections I5 of such recesses to cause binding orpinching of the vanes engaged therewith, such sections are counter-boredas at I6 to snugly receive a cylindrical extension on the cover plate 3.In the form of pump shown in Fig. 5, wherein the pump chamber is quitedeep, it is preferred that no such inner section I5 be provided becauseof the difficulty of performing a trepanning operation to such greatdepth.

Fitted into each of such recesses I3 and I4 for rocking r oscillatingmovement therein is a vane II having at least a portion of its outercylindrical surface in sliding sealing engagement with its recess topreclude the possibility of fluid bypassing between the inlet anddischarge passages of the stator. Each vane I1 is also of approximatelysemi-cylindrical form but is of greater extent than the recess in whichit is disposed so that the opposite ends I8 and t9 thereof will projectradially inward beyond the wall of bore 2 into engagement with theexterior non-cylindrical wall 2!] of the rotor 4. In the form of pumpshown in Figs. 1, 5 and 7, the vane is in the form of a relatively thinblade curved to fit into the recess in the stator, while in the pumpshown in Fig. 3, the vane is in the form of a solid cylindrical bodyprovided with a relieved face 2! to provide the rotor contacting ends I8and I9. Each vane includes a notch or recess 22 in end I9 thereof sothat such end will merely serve as a guide to hold the end I8 in sealedrelation to the rotor and to permit free passage of fluid through suchnotch or recess 22. The end I8 of each vane is disposed between eachpair of passages 9 and II and I0 and I2 to continuously separate thesame.

As indicated above, the exterior wall of the rotor 4 is non-cylindricaland it necessarily follows that in order that the ends I 8 and I9 of thevanes will continuously engage such wall during rotation of the rotorsuch wall must be of form such that the sum of the lengths of any tworadii thereof having a central angle equal to that subtended by thepoints of contact between the ends I8 and I9 of the vanes therewith is aconstant. In this way rotation of the rotor will effect a rocking backand forth of the vanes with the ends of such vanes in continuousengagement therewith. It will be observed that while the vane ends movein a circular path they are self-compensating so that they will at allpositions subtend the same central angle relative to the axis of therotor. It might be well at this point of the description to indicatethat in the form of vane shown in Fig. '7, the vane is of reduced crosssection at 23 and out of contact with recess I3. With such constructionthe ends I8 and 9 may yieldably engage the rotor whereby in spite ofslight irregularities or variations in the trueness of wall 20 therewill be a continuous engagement between the ends I8 and I9 and the wall20 without any impeding of the free rotation of the rotor as would bethe case if such ends were rigid relative to one another or withoutcausing bypassing of fluid if such variation in trueness were 4 suchthat both ends of the vane could not reach the wall 20.

The exterior wall 20 of the rotor is of radius equal to that of bore 2at three uniformly spaced points and between such points the wallgradually moves away from and closer to the wall of bore 2 to definethree pump cavities, the widest section of each pump cavity being at apoint mid-way between the points of contact of the wall 20 with the wallof bore 2. Inasmuch as there are three maximum radii and three minimumradii, the radius of wall 20 must increase and decrease from maximum tominimum and vice versa during each interval and in so doing the lengthof any two radii having a 60 central angle must total the sum of amaximum radius plus a minimum radius.

Such condition can be satisfied by any of several forms of curves aswill be presently referred to, but I prefer to use the form defined bythe following equation:

r=k+a cos 110 wherein r is the radius of the curve at any angle 0 from areference point, a is one-half the difference between the maximum andminimum radius, b is an integer determining the period of such curve,and k is the mean radius.

Applying this equation to the particular form of curve shown in thedrawing, it becomes r=7c+a cos 30 which provides six equally spaced andtrue infiection points, three of which are maximum points and three ofwhich are minimum points. all normal to radii thereto.

In Fig. 9, the equation r=lc+a cos 30 is developed or translated intorectangular coordinates, and, as shown, the curve is smooth andgradually changes from minimum to maximum and from maximum to minimumwhereby the vane ends engaged therewith will be gradually acceleratedand decelerated without mechanical shock in changing their direction ofoscillation. The curve shown in Fig. 10 comprises six similar andalternately opposite Archimedean spiral sections joined together. Suchlatter curve will also produce the result of constant sum of any tworadii having a 60 central angle therebetween but such curve does notinclude the six true inflection points and thus there will be mechanicalshock when the direction of movement of the vanes is changed from onedirection to the other. However, this shock condition can be minimizedby formin the sharp corners as shown dotted in Fig. 10;

In studying the diagrams shown in Figs. 9 and 10, it will be evidentthat during each cycle of movement of the rotor the volume of fluiddischarged from one of the discharge passages gradually varies from zeroto maximum to zero and, therefore, in order that the total dischargefrom the pump be uniform and without pulsation, it is essential that thevolume of fluid discharged from a second passage joined with the firstpassage at the same time gradually varies from maximum to zero tomaximum whereby the sum of the volumes discharged from such passages atany instant is constant. Such condition can readily be obtained byspacing the vanes apart with the ends I8 thereof in sealed engagementwith the rotor between the passages 9 and I I and II] and I2. In suchcase, the sum of the saga see 2t and 25 will be discharged and at anyinstant the sum will obviously be a constant. That is, the area of theelemental rectangle Edda multiplied by the length of the cavities.

It will be obvious to" those skilled in that while I by using a pumphaving three pumping cavities, it is possible to do'so by providing 4,5, 6 or more cavities just so long as the vanes are spaced apart atleast the extent of 1 cavities and so that there will at all times be atleast one point of sealing between the rotor wall and the stator betweensuch vanes. Of course, if elimination of pulsation is not of theessence, a pump with two cavities may be utilized in which there are twodiametrically opposed rockably mounted vanes.

In the above description and in the claims, where I have used the termscontact and engagement with reference to the stator and rotor and withreference to the vanes and rotor, it is to be understood that such termsare not to be construed to be limited to actual physical contact. Forexample,. it would be well nigh impossible to make the maximum radii ofthe rotor and the radius of the stator bore precisely the same and,therefore, in actual practice minute clearances are provided to assurefreedom of rotation of the rotor but yet provide a fluid tight seal. Thesame applies t the rotor and vanes except that in the case of the vanesof Fig. '7, there will be actual physical contact but such contact doesnot materially impede free rotation of the rotor inasmuch as it is notexcessive and is a yieldable contact.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I therefore particularly point tinctly claim as my invention:

1. A rotary pump comprising a stator member provided with a bore thereinincluding a pair of diametrically opposed inlet passages and a pair ofdiametrically opposed discharge passages, a rotor the art out anddismember rotatably mounted in such bore, said rotor member and suchbore including opposed walls in contact at circumferentially spacedpoints and defining at least three cavities between such points, and twovanes movably carried by said stator member and each having its oppositeends in contact with the wall of said rotor member, one of the ends ofone vane being disposed between one of such inlet passages and one ofsuch. discharge passages and in continuous sealed contact with suchrotor wall and one of the ends of the other vane being disposed betweenthe other of such inlet passages and the other of such dischargepassages and in continuous sealed contact with such rotor wall, thecontour of the wall with which the vane ends contact being such that thesum of the radii at the extremities of a central angle thereof subtendedby the points of contact of said vanes therewith is constant, the otherends of said vanes being formed with portions continuously haveaccomplished the desired ends 7 of I ' vided out ,ofcontact with-suchrotor wall to afford communicationbetween opposite sides of the vanes atsuch other ends thereof.

2. A rotary pump comprising a stator member provided with a borediametrically opposed of diametricallyopposed discharge passages, arotor member rotatably mounted in such bore, said rotor member and suchbore including opposed walls in contact at circumferentially spacedpoints and defining three cavities of variable radial dimension betweensuch points, and two diametrically opposed vanes movably carried by saidstator member, and each having its opposite ends in contact with thewall of said rotor member, one of the ends of one vane being disposedbetween one of suchinlet passages and one of such discharge passages andin continuous sealed contact with such rotor wall and one of the ends ofthe other vane being disposed between the other of such inlet passagesand the other of such discharge passages and in continuous sealedcontact with such rotor wall, the

contour of the wall with which the vane ends contact being such that thesum of the radii at the extremities of a central angle thereof subtendedby the points of contact of said vanes therewith is constant, the otherends of said vanes being formed with portions continuously out ofcontact with such rotor wall to afford communication between oppositesides of the vanes at such other ends thereof.

3. A rotary pump comprising a stator member provided with a cylindricalbore therein including a pair of diametrically opposed inlet passagesand a pair of diametrically opposed outlet passages, a rotor memberrotatably mounted in such bore provided with a non-cylindrical wall incontact with the wall of such bore at three uniformly spaced points andspaced therefrom between such points in such manner that the sum of thelengths of any two radial lines 60 apart to the extremities of suchrotor wall is constant, diametrically opposed vanes rockably mounted insaid stator and each provided with spaced ends in engagement with pointson such rotor wall spaced 60 apart, one end only of each vane being insealed relation to such rotor wall, and said one end of one vane beingdisposed between one of such inlet passages and one of such outletpassages and. said one end of the other vane being disposed between theother of such inlet passages and the other of such outlet passages.

4. A rotary pump comprising a stator prowith a cylindrical bore thereinincluding inlet and outlet passages, a rotor rotatably mounted in suchbore provided with a non-cylindrical exterior surface of form such thata plurality of uniformly spaced points thereof are of radius equal tothe radius of such bore and that the sum of the lengths of any two radiispaced apart a predetermined angle to the extremity of such surface isconstant, said stator being provided with an annular recess ofsemi-cylindrical form with its axis parallel to the axis of such statorbore, and a vane of arcuate form slidably engaged in such recess havingspaced ends extending inward of said stator into engagement with saidrotor at points spaced apart such predetermined angle, said vaneincluding a relatively thinner yieldable portion from one end to anintermediate portion out of engagement throughout its axial extent withone wall of such recess whereby such one end of said vane is capable ofyielding relative to the other end thereof.

therein including a pair ofinlet passages and a pair '5. A rotary :pump:comprising a stator member provided with abore therein including a pairof diametrically opposed "inlet passages and a pair of diametricallyopposed discharge passages, a rotor member rotatably mounted in suchbore, said rotor member such bore including opposed walls in contact'-at circumferentially spaced points and de'fining at least threecavities between such poirits, and two vanes movably carried by saidstator itsoppositeends incon'tact with the Wall of said rotor'mem'benoneof theends-of one vane being disposed between one of suchinlet passages and oneofsuch discharge passages and in continuoussealed-contact with such rotor wall and one of the ends of the othervane being disposed between the other of such inlet passages and theother of such discharge passages and in continuous sealed contact withsuch rotor wall, the contour of the wall with which the vane endscontact being "such that the sum of the radii at the extremities of acentral angle thereof subtended by the points of contact of said vanesmember and each having a 8 there-with is constant, the other ends of:said vanes being formed with notches therethrough affordingcommunication between opposite sides of the vanes at such otherends.

JAMES P. JOHNSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED 'STATES 'PA'IEN'I'S Number Name Date 383,811 Hoyt May 29, 1888401,203 Parker Apr. 9, 1889 993548 Ca'lkins May 30, 1911 1,972,302Hutchison Sept. 4, 1934 1,983,034 Hutchison Dec. 4, 1934 2272,6555 Davis-Feb. 10, 1942 FOREIGN PATENTS Number "Country Date 509,953 GreatBritain July 25, 1939

